*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
header{
    background:skyblue;
}
.container{
    width: 870px;
    margin: auto;
}
.clearfix::after{
    content: "";
    display: table;
    clear: both;
}
nav{
    padding:11px 0;
}
.nav-left,
.nav-center,
.nav-right{
   /* float: left;*/
    width: 33.333333%;
}
.nav-left{
    height: 56px;
}
.nav-center{
    text-align: center;
}
.nav-right{
    text-align: right;
}
.nav-right a{
    color: white;
    font-size: 13px;
    text-decoration: none;
    font-weight: bold;
}
.nav-right a img{
    display: none;
}
.banner .col{
    width: 50%;
    /*float: left;*/
}
.banner{
    color: white;
    margin-bottom: 40px;
}
.banner h1{
    margin-bottom: 15px;
    font-size: 35px;
}
.banner a{
    text-decoration: none;
    padding: 15px 53px;
    color: white;
    font-weight: bold;
    background: #15A9BE;
    transition: 0.2s;
    display: inline-block;
}
.banner a:hover{
    background: #0B86BE;
}
.banner img{
    width: 100%;
    display: block;
}
main .col{
    width: 25%;
/*    float: left;*/
    text-align: center;
    padding: 0 10px;
}
main .col img{
    margin-bottom: 10px;
}
main .col h3{
    margin-bottom: 5px;
}
main .col p{
    color: #657082;
}




@media(max-width: 600px){
    .container{
        width: 100%;
        text-align: center;
    }
    nav{
        width: 100%;
    }
    .container .nav-right a span{
        display: none;
    }

   .container .nav-right a img{
        display: block;
    }
    .banner .col{
        width: 100%;
    }
    .banner .col img{
        margin-top: 10px;
    }
    main .col{
        width: 100%;
        margin-top: 10px;
    }
}
@media(min-width:600px){
    .nav-left,
    .nav-center,
    .nav-right{
        float: left;
    }
    .banner .col{
        float: left;
    }
    main .col{
        float: left;
    }
}